s u m m a r yBackground: Non-alcoholic fatty liver disease is one of the most common chronic liver diseases. Due to the lack of definitive documentation for the effect of folic acid on fatty liver, this study was conducted to determine the relationship between serum folate levels and fatty liver in patients referred to Imam Hossain Hospital in Shahroud, in 2016. Methods: This caseecontrol study was performed on 150 patients. The case group was fatty liver patients whose disease was diagnosed based on laboratory and ultrasound findings and a control group of patients without fatty liver. After liver ultrasonography, blood samples were taken from all patients and folic acid levels were measured. Results: Of the 150 patients examined, mean BMI of patients was (25.3 ± 6.1 kg/m2 in case group and 24.8 ± 7.2 kg/m2 in control group), which was significantly higher in case group (p < 0.035). The mean fasting blood glucose level in patients was (137.5 ± 53.5 mg/dl in case group and 124.5 ± 62.5 mg/dl in control group), which was significantly higher in case group (p < 0.01). The mean LDL of the patients was (175.3 ± 65.5 mg/dl in case group and 125.5 ± 42.5 mg/dl in control group), which was significantly higher (P < 0.003) in patients with fatty liver. The mean of folic acid in patients was (3.7 ± 5.3 ng/ml in case group and 5.3 ± 4.1 ng/